Fair Value - Financial Instruments Not Carried at Fair Value (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Assets
Mortgage loans	$ 14,591	$ 14,306
Investment funds	723	750
Investment funds	156	154
Policy loans	387	417
Funds withheld at interest	48,593	15,181
Other investments	949	158
Short-term investments	165	596
Liabilities
Interest sensitive contract liabilities	141,207	102,745
Short-term Debt	0	475
Long-term debt	1,487	992
Funds withheld liability	440	408
Carrying Value
Assets
Mortgage loans	14,572	14,279
Investment funds	567	596
Policy loans	387	417
Funds withheld at interest	47,334	14,380
Other investments	840	65
Short-term investments		190
Total assets measured at fair value	80,097	46,424
Liabilities
Interest sensitive contract liabilities	92,088	57,272
Short-term Debt		475
Long-term debt	1,487	992
Securities Sold under Agreements to Repurchase	1,098	512
Funds withheld liability	390	377
Total liabilities not carried at fair value	95,063	59,628
Fair Value
Assets
Mortgage loans	15,114	14,719
Investment funds	567	596
Policy loans	387	417
Funds withheld at interest	47,334	14,380
Other investments	852	65
Short-term investments		190
Total assets measured at fair value	80,661	46,902
Liabilities
Interest sensitive contract liabilities	96,125	58,027
Short-term Debt		475
Long-term debt	1,099	1,036
Securities Sold under Agreements to Repurchase	1,098	512
Funds withheld liability	390	377
Total liabilities not carried at fair value	98,712	60,427
Level 1 | Fair Value
Assets
Mortgage loans	0	0
Investment funds	0	0
Policy loans	0	0
Funds withheld at interest	0	0
Other investments	0	0
Short-term investments		0
Total assets measured at fair value	0	0
Liabilities
Interest sensitive contract liabilities	0	0
Short-term Debt		0
Long-term debt	0	0
Securities Sold under Agreements to Repurchase	0	0
Funds withheld liability	0	0
Total liabilities not carried at fair value	0	0
Level 3 | Fair Value
Assets
Mortgage loans	15,114	14,719
Investment funds	0	0
Policy loans	0	0
Funds withheld at interest	47,334	14,380
Other investments	852	65
Short-term investments		190
Total assets measured at fair value	76,749	43,158
Liabilities
Interest sensitive contract liabilities	96,125	58,027
Short-term Debt		0
Long-term debt	0	0
Securities Sold under Agreements to Repurchase	0	0
Funds withheld liability	0	0
Total liabilities not carried at fair value	96,125	58,027
NAV | Fair Value
Assets
Investment funds	567	596
Total assets measured at fair value	3,525	3,327
Level 2 | Fair Value
Assets
Mortgage loans	0	0
Investment funds	0	0
Policy loans	387	417
Funds withheld at interest	0	0
Other investments	0	0
Short-term investments		0
Total assets measured at fair value	387	417
Liabilities
Interest sensitive contract liabilities	0	0
Short-term Debt		475
Long-term debt	1,099	1,036
Securities Sold under Agreements to Repurchase	1,098	512
Funds withheld liability	390	377
Total liabilities not carried at fair value	2,587	2,400
Related Party
Assets
Mortgage loans	640	653
Investment funds	4,808	3,550
Investment funds	1,850	819
Funds withheld at interest	13,053	13,220
Other investments	467	487
Liabilities
Interest sensitive contract liabilities	14,352	15,285
Related Party | Carrying Value
Assets
Mortgage loans	640	653
Investment funds	2,958	2,731
Funds withheld at interest	12,332	12,626
Other investments	467	487
Related Party | Fair Value
Assets
Mortgage loans	628	641
Investment funds	2,958	2,731
Funds withheld at interest	12,332	12,626
Other investments	489	537
Related Party | Level 1 | Fair Value
Assets
Mortgage loans	0	0
Investment funds	0	0
Funds withheld at interest	0	0
Other investments	0	0
Related Party | Level 3 | Fair Value
Assets
Mortgage loans	628	641
Investment funds	0	0
Funds withheld at interest	12,332	12,626
Other investments	489	537
Related Party | NAV | Fair Value
Assets
Investment funds	2,958	2,731
Related Party | Level 2 | Fair Value
Assets
Mortgage loans	0	0
Investment funds	0	0
Funds withheld at interest	0	0
Other investments	$ 0	$ 0